Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Andromeda Galaxy: 10-20 (100), 10-21 (100), 10-22 (100), 10-23 (100), 10-24 (100) — by astronomy; check the weather when the night is within four days.

2027-10-11astronomy score per night — click a bar for that night2027-11-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-10-11 Mon	95	—	unknown	00:55–06:00 (good, 5.08 h)	89.7° 00:45	9.63	87%	57.0°
2027-10-12 Tue	87	—	unknown	05:10–06:00 (good, 0.83 h)	89.7° 00:40	9.68	93%	47.4°
2027-10-13 Wed	51	—	unknown	20:20–06:00 (marginal, 9.67 h)	89.6° 00:35	9.72	97%	38.6°
2027-10-14 Thu	37	—	unknown	02:05–06:05 (marginal, 4.0 h)	89.5° 00:35	9.77	99%	31.7°
2027-10-15 Fri	33	—	unknown	20:15–22:55 (marginal, 2.67 h)	89.6° 00:30	9.81	100%	28.5°
2027-10-16 Sat	37	—	unknown	20:15–23:45 (marginal, 3.5 h)	89.7° 00:25	9.85	98%	30.4°
2027-10-17 Sun	53	—	unknown	20:10–04:00 (marginal, 7.83 h)	89.7° 00:20	9.9	94%	36.8°
2027-10-18 Mon	62	—	unknown	20:10–22:05 (good, 1.92 h)	89.6° 00:15	9.94	88%	46.1°
2027-10-19 Tue	95	—	unknown	20:10–01:00 (good, 4.83 h)	89.5° 00:15	9.98	80%	56.9°
2027-10-20 Wed	100	—	unknown	20:10–04:00 (good, 7.83 h)	89.7° 00:10	10.02	70%	68.5°
2027-10-21 Thu	100	—	unknown	20:05–05:40 (good, 9.58 h)	89.7° 00:05	10.07	59%	80.6°
2027-10-22 Fri	100	—	unknown	20:05–05:50 (good, 9.75 h)	89.7° 00:00	10.11	48%	93.0°
2027-10-23 Sat	100	—	unknown	20:05–05:55 (good, 9.83 h)	89.5° 23:55	10.15	36%	105.4°
2027-10-24 Sun	100	—	unknown	20:00–06:00 (good, 10.0 h)	89.6° 23:55	10.19	26%	117.6°
2027-10-25 Mon	100	—	unknown	20:00–05:55 (good, 9.92 h)	89.7° 23:50	10.23	16%	129.4°
2027-10-26 Tue	100	—	unknown	20:00–05:55 (good, 9.92 h)	89.7° 23:45	10.27	9%	139.9°
2027-10-27 Wed	100	—	unknown	20:00–05:50 (good, 9.83 h)	89.6° 23:40	10.31	4%	148.0°
2027-10-28 Thu	100	—	unknown	19:55–05:45 (good, 9.83 h)	89.5° 23:35	10.34	1%	151.6°
2027-10-29 Fri	100	—	unknown	19:55–05:40 (good, 9.75 h)	89.6° 23:35	10.38	0%	149.2°
2027-10-30 Sat	100	—	unknown	19:55–04:40 (good, 9.75 h)	89.7° 23:30	10.42	2%	142.3°
2027-10-31 Sun	100	—	unknown	18:55–04:35 (good, 9.67 h)	89.7° 22:25	10.46	6%	133.1°
2027-11-01 Mon	100	—	unknown	18:55–04:30 (good, 9.58 h)	89.6° 22:20	10.49	12%	122.9°
2027-11-02 Tue	100	—	unknown	18:50–04:25 (good, 9.58 h)	89.5° 22:20	10.53	20%	112.4°
2027-11-03 Wed	100	—	unknown	18:50–04:25 (good, 9.58 h)	89.7° 22:15	10.57	28%	101.8°
2027-11-04 Thu	100	—	unknown	18:50–04:20 (good, 9.5 h)	89.7° 22:10	10.6	37%	91.2°
2027-11-05 Fri	100	—	unknown	18:50–04:15 (good, 9.42 h)	89.7° 22:05	10.64	46%	80.8°
2027-11-06 Sat	100	—	unknown	18:45–04:10 (good, 9.42 h)	89.5° 22:00	10.67	56%	70.4°
2027-11-07 Sun	98	—	unknown	18:45–04:05 (good, 9.33 h)	89.6° 22:00	10.7	65%	60.3°
2027-11-08 Mon	90	—	unknown	21:05–04:05 (good, 7.0 h)	89.7° 21:55	10.74	74%	50.5°
2027-11-09 Tue	83	—	unknown	03:00–04:00 (good, 1.0 h)	89.7° 21:50	10.77	82%	41.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-10-11&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.